As is known in the art, diamond has been used as a heat spreader to remove the heat generated by high power semiconductor devices. Usually the diamond is bonded to the semiconductor chip via a metal solder or other adhesive. The semiconductor junction, where most of the heat is generated, is typically located a fair distance away from the diamond heat spreader and thus heat removal is not efficient. More particularly, processes have been developed for bonding GaN to diamond; however an interlayer is used between the GaN and the diamond. The interlayer is another thermal barrier that limits the ability of the diamond to effectively conduct heat away from the GaN epilayer. For example, in one method, a thin Si layer (˜10-20 μm thick) is used as the interlayer and in another process an oxide “glue” layer ˜10000 Å is used as the interlayer.